Liquid crystal display panel and method and device for manufacturing the same

ABSTRACT

A mixed material of liquid crystals and resin is dropped on at least one substrate in an amount greater than the amount needed to cover a display area for the LCD panel. The substrate is adhered to another substrate, and excess material is removed to the outside of a display area. The phase-separation of the liquid crystals and resin is carried out by irradiating light while pressure is added to at least one substrate, so that a liquid crystal display panel applied to a liquid crystal display device or a light shutter can be manufactured without applying a complex vacuum device.

FIELD OF THE INVENTION

This invention relates to a liquid crystal display panel applied to aliquid crystal display device or a light shutter, and further relates toa method and a device for manufacturing the same.

BACKGROUND OF THE INVENTION

Since a liquid crystal display panel can be thinned, lightened anddriven with low voltage, the panel has been applied to wrist watches,calculators, personal computers, personal word processors, and the like.However, the color and contrast of a twisted nematic (TN) liquid crystalpanel or a super-twisted nematic (STN) liquid crystal panel varies,depending on the direction from which the liquid crystal panel isviewed. In a polymer dispersed liquid crystal (PDLC) panel, liquidcrystal molecules are dispersed in a resin matrix between glasssubstrates to which electrodes are fixed, or a resin matrix is placed ina liquid crystal in a particle or network condition. When voltage is notapplied, the liquid crystal molecules are oriented randomly. Hence,there is a difference between the refractive index of the resin and thatof the liquid crystal molecules, thus scattering light (FIG. 12A). Onthe other hand, the liquid crystal molecules orient toward the directionof electric field with the application of voltage, so that therefractive index of the liquid crystal molecules becomes the same asthat of the resin and light transmits (FIG. 12B). Therefore, the PDLCpanel has high transmissivity and constant color and contrast withoutbeing influenced by the direction from which the panel is viewed.

A vacuum deposition method is known as a conventional method ofmanufacturing a liquid crystal display panel. In this method, glasssubstrates to which a pair of electrodes are fixed are washed, and aresin seal is then formed on the edge of one substrate (one section ofthe seal is left open for injection). In order to maintain apredetermined gap, spacers are dispersed on the other substrate. Then,the substrates are fixed to each other, and the resin seal is cured byheating. The panel is placed in a vacuum container in order to keep avacuum inside the panel. An injection mouth is set in contact with theliquid crystal, and the liquid crystal is then injected into the panelby changing pressure to a normal level.

However, when a highly volatile material is used in the conventionalmethod, the composition of the material changes in the process. Thus, acomplex vacuum device is necessary to keep a vacuum inside the panel. Italso takes a long time to generate a vacuum condition in the container,so that the productivity of the panels is low.

Conventional methods were proposed which include a method of droppingliquid crystals on a substrate after forming a sealing resin on thesubstrate and of pressing the resin so as to cure it (PublishedUnexamined Japanese Patent Application (Kokai) No. Sho 61-190313, KokaiNo. Hei 5-5892 and Kokai No. Hei 5-5893), a method of forming a ringedtwo-layered adhesive seal (Kokai No. Hei 5-5890), a method of droppingliquid crystals in an amount greater than the required amount on onesubstrate and of sticking substrates to each other in vacuum, whileadding pressure to the substrates so as to remove excess liquid crystalsthrough an exhaust section (Kokai No. Hei 6-235925), and a method ofcoating a mixed material of polymer and liquid crystals on a substrateapplied with a sealing material or on another substrate and of carryingout both seal cure and the phase-separation PDLC after adhering thesubstrates to each other (Kokai No. Hei 4-37820). In Kokai No. Sho61-190313, the cut surface of the substrates is sealed after pressingthe substrates so as to provide a uniform gap. However, excess liquidcrystals are liquid and the seal is in an uncured condition, so that thesubstrates are likely to slide on each other when the seal comes incontact with the liquid crystals. In this invention, on the other hand,the mixed material of liquid crystals and resin is cured when pressureis added to the substrates, so that the substrates do not slide.

In Kokai No. Hei 5-5892, Kokai No. Hei 5-5893 and Kokai No. Hei 5-5890,a pore is formed so as to remove liquid crystals, and a sealing materialis cured by adding pressure after removing excess liquid crystals.However, the pore is open when the sealing material is cured, and airbubbles may enter between substrates when pressure is set back to thenormal level. The substrates also bulge when pressure returns to theoriginal level, and a precise gap cannot be formed. In this invention,the mixed material between the substrates is cured while pressure isadded to the panel, so that no air bubbles enter and a precise gap isformed.

Particularly in Kokai No. Hei 5-5890, air bubbles remain between thefirst and second seals. In addition, since liquid crystals are liquid,remaining air bubbles enter a display area. However, since the mixedmaterial of liquid crystals and resin is cured in this invention, no airbubbles enter the display area.

Unlike in this invention, the phase-separation of liquid crystals andresin is not carried out while adding pressure to a panel in Kokai No.Hei 4-37820 and Kokai No. Hei 6-235925. In particular, Kokai No. Hei6-235925 is different from this invention in that the panel is placed ina vacuum.

SUMMARY OF THE INVENTION

It is an object of this invention to solve the above-mentionedconventional problems by providing a liquid crystal display panel havingliquid crystal sandwiched between substrates, and a method and devicefor manufacturing the liquid crystal display panel. Liquid crystals andresin, or the mixture of liquid crystals and resin, are easily injectedbetween the substrates without applying a complex vacuum device. Ahighly volatile material can also be injected between the substrates.Compared with the conventional vacuum injection method, the timerequired for manufacturing liquid crystal display panels issignificantly reduced in this invention.

In order to achieve this object, the liquid crystal display panel ofthis invention includes resin and liquid crystals sandwiched betweensubstrates. A film is formed on one section of at least one substrate. Amaterial sealed in the panel has a larger contact angle on the film thana contact angle on a central section of a display area where the film isnot formed. The resin and the liquid crystals are in a phase-separationcondition.

It is preferable that the film is formed on the edge of the substrate.

It is also preferable that the film is formed on the edge of the displayarea.

It is further preferable that the film is made of thermoplastic resin.

It is preferable that the phase separation of the resin and the liquidcrystals is carried out by irradiating light while pressure is added toat least one substrate.

It is also preferable that the resin is photosetting resin.

The liquid crystal display panel of the second aspect of this inventionincludes a pair of substrates, resin and liquid crystals. The resin andthe liquid crystals are sandwiched between the substrates. Sealing resinis continuously formed at a peripheral section of at least one of thesubstrates so as to adhere the substrates to each other. The resin andthe liquid crystals are in a phase-separation state.

The liquid crystal display panel of the third aspect of this inventionincludes a pair of substrates, resin and liquid crystals. The resin andthe liquid crystals are sandwiched between the substrates. The sealingresin is formed intermittently outside of a picture element; and theresin and said liquid crystals are in a phase-separation state.

It is also preferable that the sealing resin is formed in at least twolines, that at least one of the two lines is formed continuously at aperipheral section of at least one of the substrates, and that at leastone of the two lines is formed intermittently outside of a pictureelement.

It is further preferable that the liquid crystal display panel furtherincludes a guide path for guiding a part of the sealing resin to theoutside of the panel.

The method of manufacturing a liquid crystal panel of the inventionincludes the steps of:

dropping liquid crystals and resin or a mixed material of liquidcrystals and resin onto at least one substrate in an amount greater thanthe amount needed to cover the display area when the substrates aresealed;

adhering one substrate to the other substrate;

removing excess liquid crystals to the outside of a display area; and

carrying out the phase separation of the liquid crystals and the resinby irradiating light while pressure is added to at least one substrate.

It is preferable that light is first irradiated to the peripheralsection of the display area so as to carry out the phase separation ofthe liquid crystals and the resin, and then to the display area in orderto carry out the phase separation of the liquid crystals and the resininside the display area.

It is preferable that a film is formed before the liquid crystals andthe resin or the mixed material of liquid crystals and resin aredropped. The material sealed in the liquid crystal panel has a largercontact angle on the film than a contact angle on a central section ofthe display area where the film is not formed.

It is also preferable that the film is formed on the edge of thesubstrate.

It is further preferable that the film is formed on the edge of thedisplay area.

It is preferable that the film is made of thermoplastic resin.

It is preferable that the liquid crystals and the resin or the mixedmaterial are sealed between the substrates by dropping the liquidcrystals and the resin or the mixed material on at least one substrate,by reducing pressure while the liquid crystals and the resin or themixed material are in contact with the other substrate, and by adheringthe substrates to each other.

It is also preferable that the phase separation of the liquid crystaland the resin is carried out by irradiating light only inside thedisplay area.

It is further preferable that the phase separation of the liquid crystaland the resin is carried out, and the cut surface or a section of thecut surface of the substrates is then sealed after the liquid crystalpanel is cut.

It is preferable that the liquid crystals and the resin or the mixedmaterial of liquid crystals and resin are sealed between the substratesby dropping the liquid crystals and the resin or the mixed material onthe end section of a first substrate, by placing a second substrate soas to set it in contact with the liquid crystals and the resin or themixed material, by gradually sliding down the second substrate with acontacting section at the center, and by adhering the first and thesecond substrates to each other.

It is preferable that the resin is photosetting resin.

The device for manufacturing a liquid crystal panel includes a means ofsandwiching liquid crystals and resin or a mixed material of liquidcrystals and resin between two substrates while pressure is added to thesubstrates at a constant level, and a means of placing a lightscattering medium on at least one of the substrates and irradiatinglight from a light scattering medium side so as to carry out the phaseseparation of the liquid crystals and the resin.

It is preferable that light is irradiated from the light scatteringmedium side while a buffer is placed on the other substrate and theliquid crystal panel is pressed with a light transmitting film from thelight scattering medium side.

It is also preferable that the resin is photosetting resin.

In the method of this invention, the liquid crystals and the resin canbe sealed in-between the substrates simply by dropping a drop of liquidcrystals and resin and adhering the substrates, so that a complex vacuumdevice for keeping the liquid crystal panel in a high vacuum atmosphereis not necessary. Thus, compared with the vacuum injecting method, thetime required for manufacturing is significantly reduced and a highlyvolatile material does not change its composition by being sealedin-between the substrates.

Since the resin and the liquid crystals are in a phases-separationstate, the liquid crystals have a diameter of only about 1-2 μm.

The phase separation of the liquid crystals and the resin is carried outby the irradiation of light, and the substrates can also be sealed byirradiating light without applying sealing resin. Therefore, the timerequired for curing is shortened, and the washing process of the liquidcrystal during panel cutting and mounting processes becomes simple. As aresult, the manufacturing time of liquid crystal panels is cut, andmounting defects are reduced.

Since the film is formed on one section of at least one substrate so asto provide a larger contact angle for a material sealed in thesubstrates on the film than the contact angle at a section where thefilm is not formed, the spread of the material is prevented.

The film is formed on the edge of the substrate, so that the filmprevents the mixed material of liquid crystals and resin from being incontact with alignment marks.

The formation of the film on the edge of the display area prevents themixed material of liquid crystals and resin from spreading.

Since thermoplastic resin is applied for the film, the fluidity of thethermoplastic resin can be increased by heating after the sealing resinis cured, so that the mixed material of liquid crystals and resin canspread to a sealing section.

In the manufacturing method of the invention, the phases-separation ofthe liquid crystals and the resin is carried out and the cut surface orone section of the cut surface of the substrates is sealed after theliquid crystal panel is cut. Thus, no water gets into the liquid crystalpanel, and the substrates are sealed without applying sealing resin. Asa result, the time for curing as well as manufacturing liquid crystalpanels is significantly reduced.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of a liquid crystal display panel of afirst embodiment of the invention.

FIG. 2A is a perspective view of the liquid crystal display panel of thefirst embodiment, showing the method of manufacturing the panel.

FIG. 2B is a perspective view of substrates, showing a process ofadhering the substrates to each other.

FIG. 2C is a cross-sectional view of substrates, showing a process ofadhering the substrates to each other.

FIGS. 2D-2H is a diagram, showing the flow of a mixed material and thedisappearance of bubbles.

FIG. 3 is a view showing the method of manufacturing the liquid crystaldisplay panel of the first embodiment of the invention.

FIG. 4 is a plan view of a liquid crystal display panel of a secondembodiment of the invention, showing the method of manufacturing thepanel.

FIG. 5 is a perspective view of a liquid crystal display panel of athird embodiment of the invention, showing the method of manufacturingthe panel.

FIG. 6 is a perspective view of a liquid crystal display panel of afourth embodiment of the invention, showing the method of manufacturingthe panel.

FIG. 7 is a perspective view of a liquid crystal display panel of afifth embodiment of the invention, showing the method of manufacturingthe panel.

FIG. 8 is a perspective view of a liquid crystal display panel of asixth embodiment of the invention, showing the method of manufacturingthe panel.

FIG. 9 is a perspective view of a liquid crystal display panel of aseventh embodiment of the invention, showing the method of manufacturingthe panel.

FIG. 10 is a perspective view of a liquid crystal display panel of aneighth embodiment of the invention, showing the method of manufacturingthe panel.

FIG. 11A is a cross-sectional view of a liquid crystal display panel ofa ninth embodiment of the invention, showing a drop of mixed material ofliquid crystal and photo-curing resin on one glass substrate.

FIG. 11B is a cross-sectional view of the liquid crystal display panelshowing two glass substrates placed so that transparent conductive filmsface each other.

FIG. 11C is a cross-sectional view of the liquid crystal display panelshowing polymer dispersed liquid crystal (PDLC) being in contact withsubstrates while the inside panel is depressurized.

FIG. 11D is a cross-sectional view of the liquid crystal display panelshowing the substrates fixed to each other.

FIG. 12A is a cross-sectional view of a conventional polymer dispersedliquid crystal (PDLC) display panel showing a light scatteringcondition.

FIG. 12B is a cross-sectional view of the conventional PDLC displaypanel showing a light transmitting condition.

DETAILED DESCRIPTION OF THE INVENTION

This invention will be described by referring to the followingillustrative examples and attached figures.

EXAMPLE 1

FIG. 1 is a cross-sectional view of a liquid crystal display panel ofthe first embodiment of the invention. As shown in FIG. 1, transparentconductive films 2a and 2b (made of indium-tin oxide alloy and mentionedas ITO films hereinafter) were formed on two transparent glasssubstrates 1a and 1b so as to form a preferable pattern. After washingglass substrates 1a and 1b, alignment layers (AL5417 manufactured byJapan Synthetic Rubber Co., Ltd.) were formed as insulating films 11aand 11b on the ITO films. The panel was heated for 30 minutes at 220° C.after it was heated at 80° C. for one minute.

As spacers 5, SiO₂ particles having a diameter of 13 μm and an adherencetendency (Sinsi ball AB-8-13 μm manufactured by Catalysts & ChemicalsIndustries Co., Ltd.) were applied on glass substrate 1a. Spacers 5 wereadhered on substrate 1a after the substrate was left at 140° C. for 90minutes. Since the spacers were fixed, they were prevented from beingdisplaced by a dropped material.

On glass substrate 1b, a mixed material 6 was dropped in an amountgreater than the amount needed to cover the display area when thesubstrates are sealed. The mixed material was made of 80% by weight ofliquid crystals 3 having a diameter of about 1-2 μm (E-7 manufactured byBritish Drug House Ltd.), 1.8% by weight of polyester acrylate asphotosetting resin 4, 18% by weight of 2-ethyl hexyl acrylate, and 0.2%by weight of photosetting initiator (Darocure 1173 manufactured by MerckCo.).

Glass substrates 1a and 1b were adhered to each other so as to settransparent conductive films (ITO films) 2a and 2b facing each other.Although the substrates 1a, 1b may be adhered to each other afterdropping the mixed material of liquid crystals and resin in the displayarea as shown in FIG. 2A, a panel with a better display quality withoutbubbles can be obtained by dropping the mixed material of liquid crystaland resin 6 outside the display area 8 of the substrate 1b asillustrated in FIGS. 2B(a) and 2C(a), putting an edge of the othersubstrate 1a on the substrate 1b and gradually inclining the substrate1a along the substrate 1b as illustrated in FIGS. 2B(b) and 2C(b) sincebubbles will be removed to the outside the pixel with the flow of themixed material of liquid crystal and resin in this method. A diagram ofthe flow of the mixed material and the disappearance of the bubblesviewed from the panel plane are illustrated in FIG. 2D. The arrow inFIG. 2D shows the direction of the flow of the mixed material of liquidcrystal and resin.

As to the alignment of the substrates, an alignment mark 7 for aligningthe substrates was formed at each edge of substrate 1b and outside adisplay area 8 as illustrated in FIGS. 2A, 2B and 2C. Substrates 1a and1b were fixed to each other by aligning at these marks. Since mixedmaterial 6 was dropped in an amount more than the amount sealed betweensubstrates 1a and 1b, it protruded beyond display area 8.

As shown in FIG. 3, an "opal" diffusion glass plate (DFO-150S1manufactured by Sigma Koki Company Ltd. An "opal" diffusion glass platecomprises a transparent glass layer on which surface an opal glass layerincluding a photodiffusion material is affixed and it is well known inthe art.) 26 was adhered to one substrate (on the side of lightirradiation) of a PDLC display panel 27 and was then placed on areflector 28 made of aluminum or stainless steel so as to utilizereflection from the back surface. The reflector was placed on buffer 29which was kept at 23° C. by a circulating thermostat 30.

In order to maintain a gap between the substrates, a light transmittingfilm sheet 25 was sandwiched between the reflector and a quartz plate24, and 1 kg/cm² pressure was added to the surface of the liquid crystaldisplay panel. On the light transmitting film 25, a circulatingthermostat 23, made of a glass substrate in which water is circulatingfor keeping temperature constant, and quartz plate 24 for addingpressure were placed.

Furthermore, a heat absorbing (or reflecting) filter (for example,HAF-50S-30H manufactured by Sigma Koki Company Ltd.) 21 was placed so asto set the transmissivity of infrared rays (having 0.8 μm or morewavelength) at about zero %. An ultraviolet ray cutting filter (UV-35manufactured by Toshiba Corporation) 22 was also placed so as to excludeultraviolet rays having less than 350 nm wavelength and providing anegative effect on the liquid crystal transmission.

Then, the section except for the display area was shielded off fromlight, and light was irradiated onto the display area from the topsubstrate side with an ultra-high pressure mercury lamp (CHM-2000manufactured by Oak Seisakusho Co., Ltd.) 20 while the panel was pressedfrom the bottom substrate with 1 kg/cm² pressure. The phase separationof the liquid crystals and the resin in the panel was carried out byirradiating light with 50 mW/cm² for five minutes, and the resin wascured. The panel was then cut along the display area circumference. Thesection except the display area was removed, and ultraviolet curing typeresin (Locktite 352A manufactured by Locktite Japan Corporation) wascoated along the cut surface. Ultraviolet rays were irradiated at 55mW/cm² for ninety seconds, thus sealing the cut surface.

In this example, a mixture of liquid crystals and photosetting resin wasdropped and was injected between substrates simply, without applying acomplex vacuum deposition device. Unlike in the conventional method, itwas unnecessary to take a liquid crystal panel into a high vacuumatmosphere, so that the time required for manufacturing was cutsignificantly. Since the photosetting resin was cured, sealing resin wasnot required to seal the cut surfaces of the substrate, thus reducingthe time required for curing the resin.

Light was irradiated only to a display area, and the phase separation ofliquid crystals and resin in the display area was then carried out.Thus, the panel was easily cut and washed during the mounting process.

EXAMPLE 2

As in Example 1, a mixed material 6 of liquid crystals 3, photosettingresin 4 and photosetting initiator was dropped on a substrate 1b in anamount greater than the volume amount sealed between the substrates. Thesubstrate was then fixed to the other substrate. As shown in FIG. 4, thesection except the peripheral section of a display area was shut offfrom light, and light was irradiated only to pheripheral section 8a ofthe display area at 50 mW/cm² for five minutes, thus curing the resin.The shield at the display area was taken off, and light was irradiatedto the area at 50 mW/cm² for five minutes. As a result, the phaseseparation of the liquid crystals and the resin was carried out, and theresin was cured at the same time. The liquid crystal display panel wasthen cut along the peripheral section of the display area. Afterremoving the unnecessary section of the panel, ultraviolet curing typeresin (Locktite 352A manufactured by Locktite Japan Corporation) wascoated on the cut surface of the panel. Ultraviolet rays were irradiatedto the resin at 55 mW/cm² for ninety seconds, thus sealing the cutsurface. Since the mixed material of liquid crystals and resin outsidethe display area was applied as sealing resin in this example, it wasunnecessary to form sealing resin in advance. In addition, thephase-separation in the display area was carried out after curing theperipheral section of the display area, so that a PDLC with a uniformpanel gap was manufactured.

EXAMPLE 3

Example 3 is explained by referring to FIG. 5. Transparent conductivefilms (ITO films) were formed on two transparent glass substrates 1a and1b in preferable patterns. After washing glass substrates 1a and 1b,alignment layers (AL5417 manufactured by Japan Synthetic Rubber Co.,Ltd.) were printed on the transparent conductive films (ITO films) asinsulating films. The substrates were heated at 80° C. for one minuteand then at 220° C. for thirty minutes.

On glass substrate 1a, SiO₂ particles having an adherence tendency and adiameter of 13 μm (Sinsi ball AB-8-13 μm manufactured by Catalysts &Chemicals Industries Co., Ltd.) were dispersed as spacers. The spacerswere adhered to substrate 1a after leaving the substrate at 140° C. forninety minutes, thus preventing the spacers from being displaced bydropped mixed material. Photo-setting resin was applied at theperipheral section of substrate 1b as seal 9. SiO₂ particles havingdiameter of 13 μm (Sinsi ball B-1 manufactured by Catalysts & ChemicalsIndustries Co., Ltd.) were mixed in the photosetting resin at 0.3% byweight as the spacers. A mixed material 6 was dropped on substrate 1b inan amount greater than the amount needed to cover the display area whenthe substrates are sealed. The mixed material includes 80% by weight ofliquid crystals 3 (E-7 manufactured by British Drug House Ltd.), 1.8% byweight of polyester acrylate (photosetting resin 4), and 0.2% by weightof photosetting initiator (Darocure 1173 manufactured by Merck Co.). Asshown in FIG. 5, the seal was applied at the peripheral section of thesubstrate, and mixed material 6 of the liquid crystals and resin wasdropped inside the peripheral section.

Glass substrates 1a and 1b were adhered to each other, so that thetransparent conductive films (ITO films) faced each other. As shown inFIG. 5, an alignment mark 7 for aligning the substrates was formed ateach edge of the substrates outside display area 8. Substrates 1a and 1bwere adhered to each other by matching the marks of substrate 1a tothose of substrate 1b. Mixed material 6 was dropped between substrate 1aand 1b in an amount greater than the amount needed to cover the displayarea when the substrates are sealed, so that the material protrudedoutside the display area 8.

The phase separation of the liquid crystals and the resin inside thepanel was carried out after irradiating light from the top substrate at50 mW/cm² for five minutes while pressure at 1 kg/cm² was applied fromthe bottom substrate. The photosetting resin and seal resin 9 were curedat the same time. Then, the liquid crystal panel was cut along theperipheral section of the display area, and the unnecessary section ofthe panel was removed. Ultraviolet curing type resin (Locktite 352Amanufactured by Locktite Japan Corporation) was coated on the cutsurface, and ultraviolet rays were irradiated to the resin at 55 mW/cm²for ninety seconds so as to seal the cut surface.

Therefore, in this example, the mixed material of liquid crystals andphotosetting resin was injected between the substrates simply, withoutapplying a complex vacuum device. Since it was unnecessary to place theliquid crystal panel in a high vacuum atmosphere, the time required formanufacturing was significantly reduced. In addition, the seal wasformed at the peripheral section of the substrate in advance, so thatthe substrates are matched precisely to each other.

EXAMPLE 4

As in Example 3, the insulating films were formed on substrates 1a and1b. Adhesive spacers were scattered on substrate 1a, and a mixedmaterial was applied on substrate 1b. The mixed material was prepared bymixing SiO₂ particles having a diameter of 13 μm (Sinsi ball B-13 μmmanufactured by Catalysts & Chemicals Industries Co., Ltd.) as spacersin photosetting resin (sealing resin). As in FIG. 6, the seal was formedintermittently outside a picture element.

Glass substrates 1a and 1b were adhered to each other, so thattransparent conductive films (ITO films) faced each other. An alignmentmark 7 for aligning the substrates was formed at each edge of thesubstrates outside display area 8. By matching the marks of substrate 1ato those of substrate 1b, substrates 1a and 1b were adhered to eachother. Since mixed material 6 of liquid crystals and resin was droppedin an amount greater than the amount needed to cover the display areawhen the substrates are sealed, the mixed material protruded to outsidedisplay area 8. The seal was formed intermittently, so that somematerial protruded outside the seal, and it was unnecessary to measurethe amount of mixed material 6 precisely.

Then, the phase separation of the liquid crystals and resin in the panelwas carried out by irradiating light at 50 mW/cm² from the top substratefor five minutes while pressure at 1 kg/cm was applied from the bottomsubstrate. The resin was cured at the same time. The panel was then cutalong the peripheral section of the display area, and the unnecessarysection of the panel was removed. Ultraviolet curing type resin(Locktite 352A manufactured by Locktite Japan Corporation) was coated onthe cut surface of the substrates, and ultraviolet rays were irradiatedto the resin at 55 mW/cm² for ninety seconds so as to seal the cutsurface.

In this example, the mixed material of the liquid crystals andphotocuring resin was easily injected into the substrates withoutapplying a complex vacuum device. Unlike in the conventional method, itwas unnecessary to place the liquid crystal in high vacuum atmosphere,so that the time required for manufacturing was significantly cut. Byforming the seal intermittently outside a picture element, the liquidcrystal panel with a uniform gap was provided.

EXAMPLE 5

As in Example 3, insulating films were formed on substrates 1a and 1b.On substrate 1a, adhesive spacers 5 were scattered. On substrate 1b, amixed material was intermittently applied outside a picture element andwas continuously applied at the peripheral section of the substrate as aseal (FIG. 7). The mixed material was prepared by mixing 0.3% by weightof SiO₂ particles having a diameter of 13 μm (Sinsi B-13 μm manufacturedby Catalysts & Chemicals Industries Co., Ltd.) as spacers inphotosetting resin (sealing resin).

Glass substrates 1a and 1b were adhered to each other, so that thetransparent conductive films (ITO films) faced each other. As shown inFIG. 7, an alignment mark 7 for aligning the substrates was formed ateach edge of the substrates outside display area 8, and the alignmentmarks of substrate 1a were matched with those of substrate 1b, thusfixing the substrates. Since mixed material 6 of liquid crystals andresin was dropped in an amount greater than the amount needed to coverthe display area when the substrates are sealed, the material protrudedoutside display area 8. The seal was intermittently formed, so that themixed material also protruded outside the seal, and it was unnecessaryto measure the amount of mixed material 6 sealed between the substrates.

The phase-separation of the liquid crystals and resin inside the panelwas carried out by irradiating light at 50 mW/cm² for five minutes fromthe top substrate while pressure at 1 kg/cm² was applied from the bottomsubstrate. The resin was cured at the same time. The plate was then cutalong the peripheral section of the display area, and the unnecessarysection of the plate was removed. Ultraviolet curing type resin(Locktite 352A manufactured by Locktite Japan Corporation) was coated onthe cut surface of the substrates, and ultraviolet rays were irradiatedto the resin at 55 mW/cm² for ninety seconds, thus sealing the cutsurface.

In this example, the mixed material of liquid crystals and photosettingresin was injected between the substrates simply by dropping thematerial without applying a complex vacuum device. It was unnecessary toplace the liquid crystal panel in a high vacuum atmosphere, so that thetime required for manufacturing was significantly cut. Since the sealwas formed intermittently outside the picture element, a liquid crystalpanel with a uniform gap was provided. The seal was formed at theperipheral section of the substrates in advance, so that the substrateswere precisely matched to each other.

EXAMPLE 6

As in Example 3, insulating films were applied on substrates 1a and 1b.On substrate 1a, adhesive spacers were applied. On substrate 1b, a mixedmaterial was applied outside a picture element and at the peripheralsection of the substrate as a seal (FIG. 8). The mixed material wasprepared by adding 0.3% by weight of SiO₂ particles having a diameter of13 μm (Sinsi Ball B-13 μm manufactured by Catalysts & ChemicalsIndustries Co., Ltd.) as spacers in photosetting resin (seal resin). Apart of the seal was applied as a guide path 9a for outflowing excessmixed material to the outside.

Glass substrates 1a and 1b were adhered to each other, so that thetransparent conductive films (ITO films) faced each other. As shown inFIG. 8, an alignment mark 7 for aligning the substrates was formed ateach edge of the substrates outside display area 8. Thus, the marks ofsubstrate 1a were matched to the marks of substrate 1b. Since the mixedmaterial of liquid crystals and resin was dropped in an amount greaterthan the amount needed to cover the display area when the substrates aresealed, the material protruded outside display area 8 through the guidepath 9a.

The phase-separation of the liquid crystals and resin inside the panelwas carried out by irradiating light at 50 mW/cm² for five minutes fromthe top substrate while pressure at 1 kg/cm² was applied from the bottomsubstrate. The resin was cured at the same time. The liquid crystaldisplay panel was cut along the peripheral section of the display area,and the unnecessary section of the panel was removed. Ultraviolet curingtype resin (Locktite 352A manufactured by Locktite Japan Corporation)was coated on the cut surface of the substrates, and ultraviolet rayswere irradiated to the resin at 55 mW/cm² for ninety seconds, thussealing the cut surface.

In this example, the mixed material of liquid crystals and photosettingresin was injected between the substrates simply, by dropping the material without applying a complex vacuum device. Unlike in theconventional method, it was unnecessary to place the liquid crystalpanel in a high vacuum atmosphere, so that the time required formanufacturing was significantly cut. Since the guide path was formed,mixed material flowed out of the picture element. However, since thesubstrates were fixed by an outside seal, they were matched precisely toeach other.

EXAMPLE 7

Example 7 is explained by referring to FIG. 9. As in Example 1,transparent conductive films (ITO films) were formed on two glasssubstrates 1a and 1b. After washing glass substrates 1a and 1b, SiO₂particles having a diameter of 13 μm were scattered on glass substrate1a as spacers. As in the figure, an aqueous solution including 6% byweight of polyurethane as thermoplastic resin 10 (for example, MS6500manufactured by Mitsubishi Heavy Industries, Ltd.) was printed at theedge of glass substrate 1b. Then, the substrate was heated at 80° C. forone hour, thus forming a film. On glass substrate 1b, a mixed material 6was dropped. The mixed material was made of 80% by weight of liquidcrystals (E-7 manufactured by British Drug House Ltd.), 1.8% by weightof polyester acrylate as photosetting resin, 18% by weight of 2-ethylhexyl acrylate, and 0.2% by weight of photosetting initiator (Darocure1173 manufactured by Merck Co.).

Glass substrates 1a and 1b were adhered to each other, so that thetransparent conductive films (ITO films) were facing to each other. Analignment mark 7 was formed at each edge of the substrates outside thedisplay area. The marks of substrate 1a and those of substrate 1b werematched to each other, thus aligning substrate 1a to substrate 1b. Sincethe mixed material of the liquid crystals and resin was dropped in anamount greater than the amount needed to cover the display area when thesubstrates are sealed, the material protruded outside the display area.Thermoplastic resin 10 was formed at the edge of glass substrate 1b. Thewettability of mixed material 6 relative to thermoplastic resin 10 waspoor (the contact angle was large), so that mixed material 6 did notcome in contact with alignment marks 7 and precise alignment becamepossible. The section except for the display area of the panel wasshielded from light, and light at 50 mW/cm² was irradiated only to thedisplay area for five minutes. As a result, the phase-separation of theliquid crystals and resin in the panel was carried out, and the resinwas also cured. The panel was cut along the peripherial section of thedisplay area, and the unnecessary section was removed.

Ultraviolet curing type resin (Locktite 352A manufactured by LocktiteJapan Corporation) was coated on the cut surface of the panel, andultraviolet rays were irradiated to the cut surface at 55 mW/cm² forninety seconds to seal the cut surface.

In this example, the mixed material of liquid crystals and resin wasprevented from being in contact with the alignment marks since thethermoplastic resin was formed at the edge of the substrates.

Even though thermoplastic resin 10 was intermittently formed at theperipheral section (outside) of glass substrate 1b in this example,thermoplastic resin may be formed only at alignment marks 7. Thethermoplastic resin is not limited to the polyurethane type, and can bea polystyrene type, polyamide type, polyvinyl chloride type, orpolyethylene type. In other words, as long as the mixed material ofliquid crystals and resin has a contact angle on the thermoplastic resinthat is larger than a contact angle on the center of the display area,the resin can be used in the invention.

EXAMPLE 8

Example 8 is explained by referring to FIG. 10. As in Example 1,transparent conductive films (ITO films) were formed on two transparentglass substrates 1a and 1b. After washing glass substrates 1a and 1b,SiO² particles having a diameter of 13 μm were dispersed as spacers 5 onglass substrate 1a. Then, as shown in FIG. 10, an aqueous solutioncontaining 6% by weight of polyurethane was printed as thermoplasticresin 10 (MS6500 manufactured by Mitsubishi Heavy Industries, Ltd.) atthe edge of the display area on glass substrate 1b, and was treated withheat at 80° C. for one hour, thus forming a film. Ultraviolet curingresin was then printed as seal resin 9 at the edge of glass substrate1b.

A mixed material 6 was dropped on glass substrate 1b. The mixed materialincludes 80% by weight of E-7 (manufactured by British Drug House Ltd.)as liquid crystals, 1.8% by weight of polyester acrylate, and 0.2% byweight of photosetting initiator (Darocure 1173 manufactured by MerckCo.).

Glass substrates 1a and 1b were fixed, so that the transparentconductive films (ITO films) faced each other. Since thermoplastic resin10 was formed inside seal resin 9, mixed material 6 did not come incontact with seal resin 9 after fixing the substrates to each other,thus preventing impurities in seal resin 9 from entering mixed material6.

Then, display area 8 of the panel was shielded from light. Ultravioletrays were irradiated to seal resin 9, thus curing seal resin 9. Thepanel was then heated at 80° C. for one hour, so that the fluidity ofthermoplastic resin 10 increased and mixed material 6 was dispersed. Theshield object was removed, and light at 50 mW/cm² was irradiated to thepanel for five minutes, so that the phases-separation of the liquidcrystals and resin was carried out and the resin was cured.

In this example, the spread of the mixed material before pressing thepanel was prevented by applying the thermoplastic resin at theperipheral section of the display area. The sealing resin was formedoutside the display area in this example. However, the panel may beprepared in the following steps:

dropping the mixed material of the liquid crystals and resin;

fixing the substrates to each other;

irradiating light only to the display area;

carrying out the phase-separation of the liquid crystals and resin; and

sealing the cut surface of the substrates.

Thus, if thermoplastic resin is formed inside the display area, themixed material is prevented from being in contact with the alignmentmarks.

EXAMPLE 9

Example 9 is explained by referring to FIG. 11. As in Example 1,transparent conductive films (ITO films) were formed on two transparentglass substrates 1a and 1b. After washing glass substrates 1a and 1b,SiO₂ particles having a diameter of 13 μm were scattered on substrate 1aas spacers. As shown in FIG. 11A, a mixed material 6 was dropped onglass substrate 1b. The mixed material included 80% by weight of liquidcrystals 3 (E-7 manufactured by British Drug House Ltd.), 1.8% by weightof polyester acrylate as photosetting resin 4, 18% by weight of 2-ethylhexyl acrylate, and 0.2% by weight of photosetting initiator (Darocure1173 manufactured by Merck Co.).

Glass substrates 1a and 1b were set so as to face the transparentconductive films (ITO films) toward each other (FIG. 11B). The inside ofthe panel was depressurized to 1 Torr while PDLC was set in contact withone substrate (FIG. 11C). The substrates were fixed to each other (FIG.11D). As in Example 1, an alignment mark for fixing the substrates wasformed at each edge of substrates 1a and 1b. The marks of substrate 1awere matched to the marks of substrate 1b. The section except thedisplay area was shielded from light, and light at 50 mW/cm² wasirradiated to the display area for five minutes. As a result, thephase-separation of the liquid crystals and resin in the panel wascarried out, and the resin was then cured at the same time.

The panel was cut along the peripheral section of the display area, andthe unnecessary section was removed. Ultraviolet curing type resin(Locktite 352A manufactured by Locktite Japan Corporation) was coated onthe cut surface of the substrates, and ultraviolet rays were irradiatedto the resin at 55 mW/cm² for ninety seconds so as to seal the cutsurface.

In this example, a panel of high quality with no air bubbles wasprovided since the pressure inside the panel was depressurized to 1Torr. Since the pressure inside the panel was reduced while the mixedmaterial was in contact with the substrate, the area where the mixedmaterial contacts the atmosphere was small. Therefore, it was possibleto apply a highly volatile material in a vacuum.

The mixed material of polyester acrylate and 2-ethyl hexyl acrylate wasapplied as photosetting resin in this example. However, 2-hydroxy ethylacrylate or trimethylol propanetriacrylate may also be used in thisinvention. Besides the photosetting resin, thermosetting resin orthermoplastic resin may be applied and may be reacted with heat. As theliquid crystals, E-8 (manufactured by British Drug House Ltd.), ZLI4792(manufactured by Merck Co.), or TL202 (manufactured by Merck Co.) may beused instead. Irgacure 184 (manufactured by Chiba-Geigy Co.) or Irgacure651 (manufactured by Chiba-Geigy Co.) can be used as a polymerizationinitiator. In other words, this invention is effective without beingdependent on liquid crystal materials and resin materials. In additionto a photosetting agent, a thermosetting agent or an agent curing atordinary temperature may be applied as a sealing agent. An active matrixsubstrate having an active element can be applied as one of thesubstrates. Even though insulating films were formed on the substratesurface, the films need not be formed in this invention.

The invention may be embodied in other forms without departing from thespirit or essential characteristics thereof. The embodiments disclosedin this application are to be considered in all respects as illustrativeand not restrictive, the scope of the invention is indicated by theappended claims rather than by the foregoing description, and allchanges which come within the meaning and range of equivalency of theclaims are intended to be embraced therein.

What is claimed is:
 1. A method of manufacturing a liquid crystaldisplay panel comprising the steps of:dropping liquid crystals and resinor a mixed material of liquid crystals and resin on at least one of afirst substrate and a second substrate in an amount greater than anamount needed to cover a display area for the display panel when thesubstrates are sealed; adhering said first substrate and said secondsubstrate to each other; removing excess liquid crystals out of adisplay area; and carrying out a phase-separation of said liquidcrystals and said resin by irradiating light while pressure is added toat least one of said first substrate and said second substrate, whereinafter the phase-separation of the liquid crystals and the resin iscarried out, the first and second substrates are cut along a peripheralsection of a display area and the cut surface or a section of said cutsurface of the first substrate and the second substrate is then sealed.2. The method of claim 1, wherein the phase-separation of the liquidcrystals and the resin outside the display area is first carried out byirradiating light to a peripheral section of said display area, and thephase-separation of the liquid crystals and the resin inside saiddisplay area is then carried out by irradiating light to said displayarea.
 3. The method of claim 1, wherein the liquid crystals and theresin or the mixed material of the liquid crystals and the resin aresealed between the first substrate and the second substrate after a filmis formed on one section of at least one of said first substrate andsaid second substrate; and wherein said liquid crystals and said resinor said mixed material sealed between said first substrate and saidsecond substrate has a larger contact angle on said film than a contactangle on a central section of the display area where said film is notformed.
 4. The method of claim 3, wherein the film is formed on an edgeof the substrate.
 5. The method of claim 3, wherein the film is formedon an edge of the display area.
 6. The method of claim 3, wherein thefilm comprises thermoplastic resin.
 7. The method of claim 1, whereinthe liquid crystals and the resin or the mixed material of liquidcrystals and resin are sealed between the first substrate and the secondsubstrate by dropping said liquid crystals and said resin or said mixedmaterial onto at least said first substrate, by reducing pressure whilekeeping said liquid crystals and said resin or said mixed material incontact with said second substrate, and by adhering said first substrateand said second substrate to each other.
 8. The method of claim 1,wherein the phase-separation of the liquid crystals and the resin iscarried out by irradiating light to the display area.
 9. The method ofclaim 1, wherein the liquid crystals and the resin or the mixed materialare sealed between the first substrate and the second substrate bydropping said liquid crystals and said resin or said mixed material onan end section of said first substrate, by placing said second substrateso as to set said resin and said liquid crystals or said mixed materialin contact with an end section of said second substrate, by graduallysliding down said second substrate on said first substrate with acontacting point at a center section, and by adhering said firstsubstrate and said second substrate to each other.
 10. The method ofclaim 1, wherein the resin is photosetting resin.
 11. The method ofclaim 1, wherein, during the adhering step, the first and secondsubstrates are separated from each other by spacers located in positionsincluding the display area.
 12. A method of manufacturing a liquidcrystal display panel comprising the steps of:dropping liquid crystalsand resin or a mixed material of liquid crystals and resin on at leastone of a first substrate and a second substrate in an amount greaterthan an amount needed to cover a display area for the display panel whenthe substrates are sealed; adhering said first substrate and said secondsubstrate to each other; removing excess liquid crystals out of adisplay area; and carrying out a phase-separation of said liquidcrystals and said resin by irradiating light while pressure is added toat least one of said first substrate and said second substrate, whereinthe liquid crystals and the resin or the mixed material are sealedbetween the first substrate and the second substrate by dropping saidliquid crystals and said resin or said mixed material on an end sectionof said first substrate, by placing said second substrate so as to setsaid resin and said liquid crystals or said mixed material in contactwith an end section of said second substrate, by gradually sliding downsaid second substrate on said first substrate with a contacting point ata center section, and by adhering said first substrate and said secondsubstrate to each other.
 13. The method of claim 12, wherein thephase-separation of the liquid crystals and the resin is carried out byirradiating light to the display area.
 14. The method of claim 12,wherein, during the adhering step, the first and second substrates areseparated from each other by spacers located in positions including thedisplay area.